As stated, during the last two decades there has been tremendous activity with respect to the concept of blow molding thermoplastic containers from a descending extruded thermoplastic parison tubing. The thermoplastic material has most often been of either a polyethylene or polypropylene. The thermoplastic material is usually employed in the form of beads which are fed into the hopper of an extruder. Suitable heating means is provided whereby the beads are softened so that they may be driven as by screw means through a conventional die means.
Within the last decade additional innovations have been achieved whereby containers having unusual and complex configurations have been blow molded. Such blow molding operations are quite rapid and in most situations a plurality of the containers are blow molded at the same time, thereby further increasing the output.
During recent years a further development has occurred. In this development the blow molding step is accompanied by a step of filling the blow molded container, such as a bottle, with a liquid just prior to the completion of the blow molding operation. The blow molding operation is essentially concluded with the complete sealing of the bottle. Therefore, it is noted that when the bottle is charged with a liquid and sealed, the bottle must be breached or penetrated in order to obtain access thereto. Such access may be obtained by employing a penetrating cannula. On the other hand access to the interior can be obtained by employing a break away cap. The technique for providing a liquid charged blow molded container having a penetrable seal can be seen in U.S. Pat. No. 3,325,860. Considerable specialized improvement on the concept can be discerned from U.S. Pat. No. 3,807,713, wherein a bottle is disclosed having a specified use.
The teachings in the aforementioned U.S. Pat. No. 3,807,713 includes a built in diffuser. Unfortunately the invention therein disclosed does not result in a diffuser that is quiet when operated i.e., when gas is introduced through the diffuser. The bubbles of gas formed as a result of the use of this prior art diffuser are unduly large making for a disturbing sound when the bottle is employed close to a patient who is critically ill. Consequently, it has often been necessary to insert separate diffusers in order to achieve quiet operation.